Using lymphocyte hybridoma techniques, we have identified a Golgi-associated protein with an apparent molecular weight of 110,000 daltons. This protein was not only found in the Golgi apparatus, but in the nucleus of a subpopulation of interphase cells, as well. In addition, we found that it is identical to one of the heat-shock induced proteins. In an attempt to understand more about Golgi functions and to find a relationship between them and the heat-shock response of animal cells, we propose a careful biochemical study of this protein together study metasbolism of this protein by pulse-chase experiments, immunoprecipitation, and subcellular fractionation. We also propose to purity and charectirize this protein. The cellular localization of this protein will be investigated by immunoflourescence and immunoelectron microscopy. We will prepare more monoclonal antibodies against different determinants of this protein. We will search for cellular funtions of the 110k protein of Golgi apparatus by microinjection of these monoclonal antibodies into living cells.